[Pasdoc-main] More complete "Class Hierarchy" (by knowing "external" class hierarchy)

[Michalis K. <mic...@gm...>]

I implemented in trunk a fix/feature (depends how you look at it :) )
called "external class hierarchy". The idea is that the "Class
Hierarchy" generated by PasDoc (both in HTML page and for GraphViz
graph) was sometimes not perfect, because PasDoc doesn't know about the
hierarchy of classes defined outside of your source files.

For example: suppose you have classes A, B descending from TObject, and
classes C, D descending from Exception. Your source code contains
classes A, B, C, D, but does not contain definitions for standard
TObject and Exception classes. So PasDoc was showing them as

TObject
|- A
|- B
Exception
|- C
|- D

That is, PasDoc had no idea that class Exception descends (directly!)
from TObject.

Right now, this will be shown correctly as

TObject
|- A
|- B
|- Exception
  |- C
  |- D

A screenshot showing the two outputs side-by-side is probably better
than my ascii art :), attaching.

We now provide PasDoc with built-in knowledge of hierarchy of the common
RTL/component classes. This is encoded in
source/component/external_class_hierarchy.txt file in SVN (and processed
to .inc file and embedded in executable, just like our CSS file). This
hierarchy is taken from FreePascal RTL/FCL units, see script
source/tools/fpc_sources_parse_for_external_class_hierarchy.sh . Format
is a trivial text file with lines TChildClass=TParentName.

You can also provide your own file with class hierarchy by
--external-class-hierarchy=file.txt command-line option.

The docs are on

http://pasdoc.sipsolutions.net/ExternalClassHierarchy#preview

Everyone is welcome to share (you can paste it to that wiki page, for
example) the class hierarchy made specially for other libraries, like
Delphi RTL (if the differences between Delphi and FPC RTL will be too
much nuisance), VCL, or just any other library.

For the future:

- Implementation of --external-class-hierarchy= may be improved one day
to be able to take a dot (GraphViz) file. This would allow you to 100%
automatically generate a class hierarchy for your library, by existing
--graphviz-classes option, that can be later used by others by
--external-class-hierarchy= option. If / when I will implement it
depends on the success of this feature :), unless someone has ready
patch of course.

Michalis